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This study evaluated the efficiency of prostaglandin F2α (PGF) to hasten ovulation in weaned sows. In experiment I, weaned sows detected in estrus (0 h) received: no hormone (Control; n = 56); 0.5 mg PGF IM at 0 h and 2 h (PGF0; n = 56); or 0.5 mg PGF IM at 24 h and 26 h (PGF24; n = 55). In experiment II, weaned sows that did not express estrus signs until 72 h after weaning (0 h) were assigned to: no hormone (Control; n = 45); 10 µg buserelin acetate IM at 0 h (Buserelin; n = 43); 0.5 mg PGF IM at 34 h and 36 h (PGF; n = 44); or 10 µg buserelin acetate IM at 0 h plus 0.5 mg PGF IM at 34 h and 36 h (Buserelin + PGF; n = 45). In experiment I, no effect of PGF on the interval treatment onset to ovulation was observed (P > 0.05), and no treatment effect was observed on the relative or cumulative proportion of females that ovulated post-treatment onset (P > 0.05). In experiment II, treatment onset to ovulation interval was shorter for Buserelin group than for PGF group (P < 0.05), and a higher cumulative percentage of Buserelin treated sows ovulated up to 48 h compared to PGF and Control groups (P < 0.01), with no differences from Buserelin + PGF. Treatments did not affect total number of piglets born in both experiments (P > 0.05). In conclusion, PGF did not hasten ovulation timing or affect litter size in weaned sows., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare., (Published by Elsevier Inc.)

Synchronized cyclicity of replacement gilts is crucial to optimize breeding herd management, however, protocols with oral progestogen are expensive and require daily administration. This study tested two synchronization protocols without progestogens during the luteal phase in gilts. In Experiment I, on the day of the expression of the third estrus (D0), gilts were assigned to three groups (n = 6, each): control, with no treatment; PGF25: in which gilts received two doses of hCG (1,500 IU each) on D12 and D15 and two doses of a prostaglandin F2α (PGF) analogue (sodium cloprostenol; 250 µg) 6-h apart, on D25; and PGF30: in which gilts received two doses of hCG (1,500 IU each) on D12 and D15 and two doses of the PGF analogue (sodium cloprostenol; 250 µg) 6-h apart, on D30. The interval between PGF treatment and estrus expression was shorter in PGF30 than in PGF25 (P < 0.01). The PGF treatment failed to decrease serum progesterone (P4) for gilts from the PGF25 group (P > 0.05), but it was effective for gilts in the PGF30 group (P = 0.01). In Experiment II, gilts were assigned to three groups (n = 12, each): control (no treatment); eCG+hCG (400 IU eCG on D10 plus 500 IU hCG on D12); and hCG2 (two hCG doses, 1,500 IU each on D12 and D15). On D30, gilts from eCG+hCG and hCG2 that did not express estrus received two doses of the PGF analogue (250 µg each, 6-h apart). All gilts were inseminated when estrus was detected. Serum P4 concentrations were similar for all groups on D10 (P > 0.05) and greater on D20 and D25 for gilts in eCG+hCG and hCG2 (P < 0.01) than for those in the control, whereas P4 concentration was greater in hCG2 than in eCG+hCG, on both moments. The inter-estrus interval (IEI) was shorter for control gilts and intermediate for gilts in eCG+hCG, while the longest IEI was observed for gilts in hCG2 (P < 0.01). Total litter size was larger for gilts in the control (P = 0.02) compared to those in hCG2 and did not differ from the other groups for gilts in eCG+hCG (P > 0.05). In conclusion, Experiment I showed that PGF treatment did not induce luteolysis 10 days after the second hCG treatment but it was effective 15 days after the second hCG application. Additionally, Experiment II showed that both eCG+hCG and hCG2 were efficient in prolonging the luteal phase; however, number of piglets born alive and total litter size were negatively affected by the hCG2 protocol. In this sense, treatment with eCG+hCG or hCG2 may represent a steroid-free approach to prolong the luteal phase in gilts, although the doses and number of treatments must be further investigated., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Two experiments were performed to evaluate the use of an intravaginal device (IVD) impregnated with medroxyprogesterone acetate (MPA) to avoid early parturition and synchronize farrowing in sows. In both experiments with IVDs, the gestation length, stillbirth rate, birth weight, colostrum yield, lactational litter performance, and subsequent reproductive performance of sows were assessed. In Experiment 1 (Exp. 1; n = 91), sows were assigned to four treatments to evaluate the minimum required MPA dose: without IVD (CONT; control), 400 mg (MPA400), 600 mg (MPA600), and 800 mg (MPA800) of MPA in the IVD. The IVD was inserted on day 110 of gestation and removed on day 115. No sows farrowed during IVD treatment. Gestation length was increased in treatments with MPA (116.4 days) compared to the control (CONT; 114.9 days; P < 0.01), without effects on piglet birth weight (P = 0.98). A lower percentage of deaths around the farrow (P = 0.02) was observed in the CONT (1.8%) compared to MPA treatments (6.8%). The dose of 400 mg of MPA, validated in Exp. 1, was used in Experiment 2 (Exp. 2; n = 84) to evaluate the performance of sows and piglets in a sow farrowing synchronization protocol. Sows were treated with MPA from days 110-114 of gestation with or without 0.168 mg of cloprostenol sodium (PGF2α), for luteolysis induction, at IVD removal. Thus, four treatments were considered: CONT - without MPA or luteolysis induction (no interventions); PGF2α - luteolysis induction on day 114 of gestation without MPA; MPA114 - MPA treatment till 114 days of gestation without luteolysis induction; MPA114 + PGF2α - MPA treatment and luteolysis induction on day 114 of gestation. The gestation length in treatments with IVDs was longer (P < 0.01) than CONT without a difference for PGF2α treatment (P = 0.46). No impact of IVD use on piglet birth weight (P = 0.67) and deaths around the farrow (P = 0.50) were observed. The colostrum yield (P = 0.65), immunocrit (P = 0.72), piglet performance during lactation (P = 0.81), and weaning-to-estrus interval (P = 0.21) were similar among treatments. In conclusion, the use of IVDs impregnated with 400 mg of MPA between days 110 and 114 of gestation prevented early parturition with no implications for piglet survival at birth, colostrum yield, or litter performance., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest. The funding sponsors had no role in the design of the study, collection, analysis, and interpretation of data, writing of the manuscript, and the decision to publish the results., (Copyright © 2022 Elsevier Inc. All rights reserved.)

High-quality follicles result in larger corpora lutea (CL), producing more progesterone, and having a fundamental role in pregnancy maintenance. For some sows, follicular growth takes place during lactation, and follicle selection occurs under a catabolic environment. As altrenogest inhibits follicular development, this study aimed to evaluate follicular growth, CL size, estrus expression, and subsequent reproductive performance of sows treated with altrenogest during the last seven days of a three-week lactation. A total of 81 primiparous and 319 multiparous sows were allocated to two treatments: CONT (control group) and ALT (20 mg of altrenogest/day during the last seven days of lactation). Subsamples of 20 primiparous sows and 97 multiparous were randomly selected to evaluate follicular growth and 26 multiparous sows for serum progesterone analysis at day 21 of gestation. On day 21 of pregnancy, CL measurement was performed by ultrasound. Once in estrus, sows were post-cervically inseminated with pooled semen doses with 1.5 × 10 9 sperm cells at estrus onset and every 24 h during the standing reflex period. Sows not showing estrus until 10 days after weaning were considered in anestrus. The variables weaning-to-estrus interval, CL size, litter size in the subsequent cycle, and piglet birth weight were evaluated using the GLIMMIX procedure and compared using the Tukey-Kramer test. Anestrus, pregnancy, farrowing, and adjusted farrowing rate were evaluated as binary responses using logistic regression. Follicular size was analyzed as a repeated measure during treatment and after weaning. Treatment was considered as a fixed effect. During the treatment period, follicular size was smaller in ALT sows than CONT sows (3.29 vs. 3.52 mm; P < 0.001). However, after treatment, ALT sows showed a larger follicular size than CONT sows (5.30 vs. 5.03 mm; P ≤ 0.01). There were less ALT sows showing estrus than CONT sows on days three (1.03 vs. 4.57%) and four (55.38 vs. 68.02%) after weaning (P ≤ 0.05), respectively. At 21 days after insemination, ALT sows showed larger CL size and lower CL size variation (P < 0.01) than CONT sows. Anestrus rate, pregnancy rate, farrowing rate, adjusted farrowing rate, litter size in the subsequent cycle, piglet birth weight, litter birth weight, and birth weight variation did not differ between treatments (P ≥ 0.14). In conclusion, altrenogest treatment during the last week of lactation concentrated estrus expression on day five after weaning, larger follicle and CL sizes; however, with no improvement in reproductive performance., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

This study evaluated reproductive indicators of gilts treated with altrenogest or an intravaginal device (IVD) containing medroxyprogesterone acetate (MPA) for estrous cycle synchronization, starting the protocol on different days of the estrous cycle or replacing the IVD in the middle of treatment. In Experiment 1, 126 gilts were assigned, according to the day of treatment onset (Day 5 or 10 of the estrous cycle), to the following treatments: Control-5 (no hormone); Control-10 (no hormone); IVD-5 (IVD with MPA); IVD-10 (IVD with MPA); ALT-5 (altrenogest); or ALT-10 (altrenogest). The first day of the previous estrus was considered as Day 0 of the estrous cycle, and progestogen groups were treated for 14 d. In Experiment 2, 63 gilts were assigned to Control, ALT, or IVD groups. Progestogen treatment started on Day 10 of the estrous cycle, and the IVD was replaced after 7 d of treatment. In both experiments, no gilts expressed estrus during progestogen administration. In Experiment 1, the interval hormonal withdrawal-to-estrus (IHE) tended to be shorter when treatment started on Day 10 than on Day 5 (3.6 vs. 4.1 d, respectively; P = 0.09). The percentage of gilts expressing estrus after hormone withdrawal was lower for IVD-gilts (76.3%) compared to ALT (100%) and Control-gilts (92.9%; P ≤ 0.07). The percentage of persistent follicles (PFOL) was greater in IVD-10 (60.0%) and ALT-10 (33.3%) than CONT-10 (0.0%; P ≤ 0.06). The adjusted farrowing rate (AFR) was lower in IVD (65.5%) and ALT (80.5%) compared with CONT (97.4%; P ≤ 0.08). In Experiment 2, the IHE was longer for ALT than IVD (4.9 vs. 3.9 d, respectively; P < 0.01). No difference among groups was observed in the percentage of gilts expressing estrus (overall 86.4%), but the occurrence of PFOL was higher in IVD (61.5%) compared to ALT (5.3%), and Control groups (10.5%; P < 0.01). The AFR was lower in IVD (53.8%) than in ALT (88.2%) and Control (94.7%; P ≤ 0.05). The total number of piglets born was not affected by hormonal treatments in either experiment. Estrous expression was delayed in gilts treated with altrenogest or IVD-MPA. However, the reproductive performance of IVD-gilts was compromised, which was not circumvented by IVD replacement in the middle of treatment. Therefore, further studies are necessary to understand MPA pharmacodynamics and investigate alternative devices for a steady release of progestogens in gilts., Competing Interests: Declaration of competing interests The authors declare no conflicts of interest. The funding sponsors had no role in the design of the study, collection, analyses, and interpretation of data, writing of the manuscript, and the decision to publish the results., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The aim of this study was to observe the effects of neoadjuvant therapy with irinotecan and 5-fluorouracil (5-FU)/folinic acid (FA) on the resection rate and survival of colorectal cancer patients with initially unresectable hepatic metastases., Patients and Methods: Forty patients received neoadjuvant chemotherapy comprising irinotecan 180 mg/m(2) administered intravenously (i.v.) on day 1, FA 200 mg/m(2) i.v. on days 1 and 2, 5-FU 400 mg/m(2) i.v. bolus on days 1 and 2, and 5-FU 1200 mg/m(2) as a continuous 48-h i.v. infusion on day 1. The treatment was repeated every 2 weeks and response was assessed every 12 weeks (six cycles)., Results: The objective response rate to chemotherapy was 47.5% (n = 19), with two complete responses and disease stabilization in 11 (27.5.%) patients. Responses were unconfirmed for 11 patients undergoing surgery within 2 weeks. Treatment was well tolerated and adverse events were typical of the chemotherapy agents used. Twenty-seven (67.5%) patients reported hematological toxicity (35.0% grade 3/4) and 14 (35.0%) reported gastrointestinal toxicity (12.5% grade 3/4). Thirteen patients (32.5%) underwent potentially curative liver resection following chemotherapy. Chemotherapy was particularly effective in patients with large metastases on entry to the study. The median time to progression is 14.3 months and, at a median follow-up of 19 months, all patients are alive., Conclusions: Neoadjuvant therapy with irinotecan combined with 5-FU/FA enabled a significant proportion of patients with initially unresectable liver metastases to undergo surgical resection. The effects of treatment on survival have yet to be determined.